[lld] r306304 - [COFF] Fix SECREL and SECTION relocations against common symbols

[Reid Kleckner via llvm-commits]

Author: rnk
Date: Mon Jun 26 09:45:36 2017
New Revision: 306304

URL: http://llvm.org/viewvc/llvm-project?rev=306304&view=rev
Log:
[COFF] Fix SECREL and SECTION relocations against common symbols

Summary:
They do the obvious thing: provide the section index of .bss and the
offset of the symbol in .bss.

Reviewers: ruiu

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D34628

Added:
    lld/trunk/test/COFF/secrel-common.s
Modified:
    lld/trunk/COFF/Symbols.h
    lld/trunk/COFF/Writer.cpp

Modified: lld/trunk/COFF/Symbols.h
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/COFF/Symbols.h?rev=306304&r1=306303&r2=306304&view=diff
==============================================================================
--- lld/trunk/COFF/Symbols.h (original)
+++ lld/trunk/COFF/Symbols.h Mon Jun 26 09:45:36 2017
@@ -187,6 +187,8 @@ public:
   }
 
   uint64_t getRVA() { return Data->getRVA(); }
+  uint32_t getSecrel() { return Data->OutputSectionOff; }
+  uint16_t getSectionIndex();
 
 private:
   friend SymbolTable;

Modified: lld/trunk/COFF/Writer.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/COFF/Writer.cpp?rev=306304&r1=306303&r2=306304&view=diff
==============================================================================
--- lld/trunk/COFF/Writer.cpp (original)
+++ lld/trunk/COFF/Writer.cpp Mon Jun 26 09:45:36 2017
@@ -215,6 +215,8 @@ uint32_t Defined::getSecrel() {
   switch (kind()) {
   case DefinedRegularKind:
     return cast<DefinedRegular>(this)->getSecrel();
+  case DefinedCommonKind:
+    return cast<DefinedCommon>(this)->getSecrel();
   case DefinedSyntheticKind:
     return cast<DefinedSynthetic>(this)->getSecrel();
   default:
@@ -235,6 +237,8 @@ uint16_t Defined::getSectionIndex() {
     return D->getChunk()->getOutputSection()->SectionIndex;
   if (isa<DefinedAbsolute>(this))
     return DefinedAbsolute::OutputSectionIndex;
+  if (auto *D = dyn_cast<DefinedCommon>(this))
+    return D->getSectionIndex();
   if (auto *D = dyn_cast<DefinedSynthetic>(this)) {
     if (!D->getChunk())
       return 0;
@@ -244,6 +248,10 @@ uint16_t Defined::getSectionIndex() {
         toString(*this));
 }
 
+uint16_t DefinedCommon::getSectionIndex() {
+  return Data->getOutputSection()->SectionIndex;
+}
+
 bool Defined::isExecutable() {
   const auto X = IMAGE_SCN_MEM_EXECUTE;
   if (auto *D = dyn_cast<DefinedRegular>(this))

Added: lld/trunk/test/COFF/secrel-common.s
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/COFF/secrel-common.s?rev=306304&view=auto
==============================================================================
--- lld/trunk/test/COFF/secrel-common.s (added)
+++ lld/trunk/test/COFF/secrel-common.s Mon Jun 26 09:45:36 2017
@@ -0,0 +1,41 @@
+# RUN: llvm-mc %s -filetype=obj -triple=x86_64-windows-msvc -o %t.obj
+# RUN: lld-link -entry:main -nodefaultlib %t.obj -out:%t.exe
+# RUN: llvm-readobj %t.exe -sections -section-data | FileCheck %s
+
+# Section relocations against common symbols resolve to .bss.
+
+# CHECK: Sections [
+# CHECK:   Section {
+# CHECK:     Number: 1
+# CHECK:     Name: .bss (2E 62 73 73 00 00 00 00)
+# CHECK:     VirtualSize: 0x4
+# CHECK:   }
+# CHECK:   Section {
+# CHECK:     Number: 2
+# CHECK:     Name: .rdata (2E 72 64 61 74 61 00 00)
+# CHECK:     SectionData (
+# CHECK:       0000: 00000000 01000000 |........|
+# CHECK:     )
+# CHECK:   }
+# CHECK:   Section {
+# CHECK:     Number: 3
+# CHECK:     Name: .text (2E 74 65 78 74 00 00 00)
+# CHECK:     VirtualSize: 0x1
+# CHECK:     SectionData (
+# CHECK:       0000: C3                                   |.|
+# CHECK:     )
+# CHECK:   }
+# CHECK-NOT: Section
+# CHECK: ]
+
+.text
+.global main
+main:
+ret
+
+.comm   common_global,4,2
+
+.section .rdata,"dr"
+.secrel32 common_global
+.secidx common_global
+.short 0